Omega-3 fatty acids in fish may not enhance results of antidepressant drugs

A new study published in the Oct. 21 (2009) issue of the Journal of the American Medical Association, find that fish oil does not enhance the results of the antidepressant, sertraline (Zoloft) when taken with Omega-3 fatty acids found in fish.

“Unfortunately, it’s not where we wanted to be. We were kind of disappointed, to say the least,” said study author Robert M. Carney, a professor of psychiatry at Washington University School of Medicine in St. Louis.

The study included 122 patients with major depression and coronary heart disease who took 50 milligrams of Zoloft a day, then were randomized to receive either 2 grams a day of omega-3 acid ethyl esters or a corn-oil placebo capsule.

There was no difference in depression scores before and after 10 weeks of treatment. However the study notes redesigning the study to change amount of Zoloft, dose of fish oil, form of fish oil or duration of treatment may change the outcome of this study.

“The problem, from our point of view, is that that’s just not good enough,” he added. “It’s definitely better than placebo, better than doing nothing. We’re trying to find a treatment or combination of treatments that’s going to significantly improve the depression outcome.”

“We’re still exploring other possibilities,” Carney said.

That includes an increased dose of omega-3, increasing the duration of the study and identifying perhaps subsets of patients who may respond to this combination treatment better than prescription antidepressants alone.

But it’s not time to stop taking fish oil capsules yet, one expert said.

“The American Heart Association still does have recommendations based on the data we do have,” said Dr. John Erwin III, professor of internal medicine at Texas A&M Health Science Center College of Medicine, and senior staff cardiologist with Scott & White Hospital in Temple.

“We also use fish oil to reduce triglyceride levels and it’s very effective in that use. I wouldn’t encourage people who are taking fish oil caplets to stop it now because of this study. It just means we have a little bit more work to do on the depression side of things,” he said.

The study was funded by the U.S. National Heart, Lung, and Blood Institute. GlaxoSmithKline Inc. provided both omega-3 and placebo capsules, while Pfizer supplied the Zoloft.

SOURCES: Robert M. Carney, Ph.D., professor, psychiatry, Washington University School of Medicine, St. Louis; John Erwin III, M.D., associate professor of internal medicine, Texas A&M Health Science Center College of Medicine, and senior staff cardiologist, Scott & White Hospital, Temple; Oct. 21, 2009, Journal of the American Medical Association